Lightweight concrete with improved thermomechanical properties incorporating PCM-infused microsilica additives

The increasing need for environmentally sustainable building materials has positioned lightweight concrete (LWC) as a promising solution, offering benefits such as reduced weight and improved thermal and acoustic properties. However, previous studies indicate that incorporating lightweight aggregates (LWA) into LWC can adversely affect the material's mechanical properties. Furthermore, the potential integration of phase-change materials (PCMs) in LWC remains largely unexplored, particularly under challenging environmental conditions. To address these gaps, this study investigates the controlled use of lightweight expanded clay aggregate (LECA) and micro-silica infused with polyethylene glycol (PEG) 600 and 1000 as PCMs to develop LWC with superior mechanical and thermal properties. A novel “simulated solar exposure and moisture conditioning test” and a thermal behavior evaluation test are introduced. Additional mechanical and thermal tests, including measurements of compressive strength and thermal conductivity, were conducted to optimize LWC properties for warm, humid climates. The results indicate that, although water absorption increased with higher LECA contents, PEG 1000 reduced it by 67%. Thermal conductivity decreased with increasing LECA content and further decreased with PEG 1000 infusion, achieving a 64% reduction. The sunlight and humidity simulation test also demonstrated the superior thermal stability of PEG 1000-infused mixtures. These findings highlight the potential of PCM-integrated LWC to enhance energy efficiency and thermal performance, offering significant advancements for sustainable building design.